Question

Compare all the proposed models of an atom given in chapter​

Answer 1

Answer:

Compare all the proposed models of an atom given in this chapter. (i) An atom consists of a positively charged sphere and the electrons are embedded in it. ... (ii) The electrons revolve around the nucleus in well-defined orbits. (iii) The size of the nucleus is very small as compared to the size of the atom.

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Answer 2

Answer:

Thomson's model of an atom:

1. An atom consists of a sphere of positive charge with negatively charged electrons embedded in it.

2. The positive and the negative charges in an atom are equal in magnitude due to which an atom is electrically neutral.

Rutherford's model of an atom:

1. There is a positively charged, highly densed centre in an atom called the nucleus. Nearly the whole mass of an atom resides in the nucleus.

2.The electrons revolve around the nucleus in circular path.

3. The size of the nucleus is very small compared to the size of an atom.

Bohr's model of an atom:

1.An atom is made up of 3 particles electrons, protons and neutrons. Due to the presence of equal number of electrons and protons, atom on the whole is electrically neutral.

2. The protons and neutrons are located inside the nucleus due to which nucleus is positively charged.

3. The electrons revolve around the nucleus in fixed paths called orbots or shells or energy levels. The energy levels are represented as K,L,M,N or 1,2,3,4,5,.....

4. There is a limit to the number of electrons each energy level can hold. It is given by the formula 2n^2 where n is the orbit number .

5. Each energy level is associated with fixed amount of energy, the shell nearest to the nucleus having minimum amount of energy and the one farthest having maximum energy.

6. There is no change in the energy of electrons as they keeping revolving in the same shell and the atom remains stable.